Merge pull request #2 from sebasguts/master

ToDo Lists
Merge pull request #3 from sebasguts/master

Fixed doc entries
updated .gitignore
Merge pull request #4 from sebasguts/master

Design fix
Merge pull request #5 from sebasguts/master

Some changes
Merge pull request #6 from sebasguts/master

Latest changes
Merge github.com:sebasguts/ToolsForHomalg into devel

* github.com:sebasguts/ToolsForHomalg:
  Added contrapositions.
  More documentation.
  Added trees and used them in ToDo-lists.
Merge branch 'master' into devel

* master:
  updated .gitignore
Added new functionality, changed syntax.

More Blueprints to come. Code needs some
cleanup. Tracking objects will become availible soon.